I would say 80-90% of just water doused PC's come back to life.
It all depends on how long it was plugged in, and where the water went.
Pull the doors off, pull cards out, lay it all on a anti static mat or bag, then add low heat for a while.
I like to set them in the sun from a window for a day while plenty of air is blown over it.
If it's really soaked, I use alcohol to clean anything up that's really dirty, and then dry it out.